It has been a conventional practice to use the superfinishing process to finish a crown surface (hereinafter, also referred to as “CR surface”) of a cylindrical roller bearing, a tapered roller bearing or the like.
As disclosed in Japanese Unexamined Patent Publication No. 2002-326153, for example, the superfinishing process is performed as follows. A tip of the superfinishing stone is pressed against an inner peripheral surface (subject surface) of an outer ring or an outer peripheral surface of an inner ring rotated about its center axis, so as to be slid on the inner peripheral surface or outer peripheral surface. In the meantime, the superfinishing stone is vibrated (oscillated) in a different direction from the sliding direction. The superfinishing stone is disposed in a manner to incline to a perpendicular to a raceway surface of the outer ring or inner ring and toward an outer side of a diametrically greater opening. Thus is avoided interference between a rear end portion of the superfinishing stone and a non-subject raceway surface opposite from a subject raceway surface (on which the tip of the superfinishing stone is slid). This permits the superfinishing stone to be increased in the longitudinal length thereof, so that the frequency of replacement of the superfinishing stone may be reduced.